HIGHLAND PARK (AP) — U.S. Sen. Mark Kirk said he often visualized climbing the 45 steps of the U.S. Capitol as a source of inspiration during his months of grueling physical therapy after suffering a major stroke last year.

Kirk hopes to accomplish that goal on Thursday when he plans to return to the Senate.

In an interview with the (Arlington Heights) Daily Herald (http://bit.ly/Ukrj2X ) the Illinois Republican called the stroke "the hardest thing I've ever overcome and the biggest lesson in life I have ever learned by a country mile."

The massive stroke limited movement on the left side of his body and affected his speech. He spent months learning to walk and climb stairs, along with speech therapy, at the Rehabilitation Institute of Chicago.

Kirk, 53, now speaks more slowly and deliberately. He also uses a four-pronged cane and may need a wheelchair. He is expected to have a scaled back schedule and won't keep the same busy travel schedule he once did.

He said the stroke gave him a renewed sense of purpose, deepened his faith and the experience made him vow "to never, ever give up."

"I would say that I definitely became much more religious," Kirk told the newspaper. "They say there are no atheists in foxholes, and this stroke put me into a very deep foxhole. Yet, that feeling of faith sustained me, so I have no feelings of anger or regret."

Kirk briefly returned to his Senate office in Washington last month for the first time since the stroke and met with aides. During his rehabilitation, he held videoconferences with staffers and kept in contact through email and phone.

Doctors have said that Kirk made excellent progress during his rehabilitation, which included grueling physical workouts as part of experimental therapy. In November he climbed 37 floors inside Chicago's Willis Tower as part of a charity event.

Kirk's office kept the public updated on his progress with video updates and statements. He also campaigned for fellow Republicans leading up to the Nov. 6 election.

"My hope was my recovery would be easily understood and very public and very transparent," Kirk said. "Most times the public figures cover up the big problem they have."